The boot is not what seals.
There is a rubber plug that goes in the hole in the carb that then the centre pin pushes into it. The boot goes on and the cross pin goes in.
I would say you need a new plug and boot.
Other than that it could be an adjustment issue with the cable. Thats an art to work out.
Or it could be a carb problem, diaphragm or spring issue.
Sounds a bit to me like it could be flooding.
Could be a spark issue, it should be blue.
Thats quite a few things so it could be anything realy.
Im not much help am i.
